Enchancement: A suggest for a more smart callback.

[c-pointer]

Since muParser does not support stdarg (which is much more power full than all those callbacks)
A suggest a more smart callback,

f(const char *fmt, double *array, int size_of_array)

So I could write more complicated queries.

Thank you :)

[beltoforion]

That seems doable. What kind of queries do you want to write that require more numeric parameters than 5?

[c-pointer]

Nothing, the fmt is all the meaning, the final string and the of parameters... The fmt can be used to get the number of parameters, but you may want it NULL, just to pass the specified number of parameters.

As user, with this I don't need several callbacks for similar cases.
You are late to answer and I forgot what exactly I could need to (wasn't for optimization).

Plus I found it is optimized generic API for your class.

I was wrote something similar, may it help you with the format (fmt):
It seems bug-free but wasn't tested enough.

// printf(...)
static int pf(const vector<CVar>& args, CVar *result) {
	if ( args.size() > 0 ) {
		const char *p = args[0].gets().c_str();
		size_t	pos = 0;
		char	buf[256], *t = buf;
		char	fmt[16], *f = fmt;
		int		count;

		while ( *p ) {
			if ( *p == '%' && *(p+1) == '%' ) {
				p += 2; *t ++ = '%';
				continue;
				}
			else if ( *p == '%' ) {
				f = fmt;
				while ( *p ) {
					*f ++ = *p ++;
					if ( strchr("sSfFgGeEdiXxu", *(p-1)) != NULL ) break;
					if ( (f - fmt) == 15 ) break;
					}
				*f = '\0';
				if ( toupper(*(p-1)) == 'S' )
					count = sprintf(t, fmt, args[++ pos].gets());
				else if ( toupper(*(p-1)) == 'F' || toupper(*(p-1)) == 'E' || toupper(*(p-1)) == 'G' )
					count = sprintf(t, fmt, args[++ pos].getf());
				else
					count = sprintf(t, fmt, args[++ pos].geti());
				if ( count > 0 )
					t += count;
				continue;
				}
			*t ++ = *p ++;
			}

		*t = '\0';
		result->sets(buf);
		return 0;
		}
	throw runtime_error("no format specified");
	}

[beltoforion]

Ok, thank you for the context.